Radiation from CT Scans Associated With These Cancers

Radiation exposure from computed tomography (CT) scans is associated with an increased risk of thyroid cancer and leukemia, according to a study published in JNCI Cancer Spectrum.

Researchers conducted a nested case-control study in a cohort constructed from a population-based universal health insurance dataset in Taiwan from 2000 to 2013.

The study included 22,853 thyroid cancer, 13,040 leukemia, and 20,157 non-Hodgkin lymphoma (NHL) cases. Median follow-up was more than nine years. Patients were excluded if they were younger than 25 years at the time of cancer diagnosis, had less than three years of follow-up before cancer diagnosis, or had a history of a cancer before the year 2000.

Exposure associated with cancers and impacted by patient age, sex

Exposure to radiation from CT scans was associated with an increased risk of thyroid cancer (odds ratio [OR] = 2.55; 95% CI, 2.36-2.75) and leukemia (OR=1.55; 95% CI, 1.42-1.68). This increased cancer risk was stronger in females compared with males.

There was no significant association between the risk of cancer and CT scans in patients with NHL (OR=1.05; 95% CI, 0.98-1.12); however, there was an increased risk of NHL in patients ≤45 years of age.

“[A] clear dose-response relationship was observed in patients ≤45 years of age for all three cancer types,” the researchers concluded.